While there are a variety of factors to consider carefully before entering aviation, the 1500 rule is not one of them.
Historically, 1500-2500+ hours was the competitive norm for entry-level airline pilots. Most of us older folks had that much before we got hired, and there are several ways to do it. With a few rare exceptions, nobody goes directly from pilot training to airline pilot in the US.
Flight Instruction: This is the normal path for new pilots, those who do not have 1000+ hours as a CFI are the exception not the rule. The challenge here is that you will probably need several hundred hours of multi-engine, and not many schools do much or any ME training). This means you will either have to seek out a school which does ME training so you can eventually work as an MEI, or find another job flying light twins.
135 freight: Another traditional career stepping-stone. You normally take this step after you have 1200 hours as a flight instructor. The schedules are bad (usually fly at night) with most of your days spent hanging around remote airports for low pay and poor benefits. But you can usually move up to a twin-engine airplane pretty quickly, and may also get turbine experience.
There are other jobs, but they are not as easy to come by or do not involve the type of flying which airlines prefer. Traffic watch, pipeline patrol, environmental monitoring, skydive pilot, etc.
As far as other options...
Military: Do it if you can...compensation, benefits, training, and future career prospects are a lot better than in civilian aviation. Of course there are other things to consider before deciding on the military.
Freight: I mentioned 135 freight...most folks don't want to do that for a career. The good freight jobs are actually better than passenger airline jobs, but of course they are far more competitive too. Follow the passenger airline career track, and after you are a regional CA you can consider freight as an option.
Corporate: This is a whole different animal, but the path starts out the same. Try to get 1500 hours and an ATP. Even more so than airlines this industyry is ALL about who you know, so you will definitely want to take every opportunity to meet people and network. Once you start flight training you will learn about who's who at the airport.
Oh, yeah...get a college degree in a non-aviation field which will serve as a backup career. Trust Me.